[Human parvovirus B19-induced hemophagocytic lymphohistiocytosis and myocarditis in an adult patient with hereditary spherocytosis]

Human parvovirus B19 (HPV-B19) causes hemophagocytic lymphohistiocytosis (HLH). Here we describe a 35-year-old female with hereditary spherocytosis (HS) who developed HLH due to HPV-B19 infection. Upon admission, she had high fever and diarrhea. Laboratory findings included severe pancytopenia and elevated serum triglyceride and ferritin levels. Moreover, high HPV-B19 levels in the peripheral blood and increased reactive lymphocytosis in the bone marrow led to a diagnosis of HLH due to HPV-B19 infection. With supportive therapy and a blood transfusion, HLH symptoms, including fever and myelosuppression, improved in 1 week. However, symptoms of heart failure (HF) suddenly developed, and an echocardiography revealed diffuse systolic dysfunction, suggesting viral myocarditis due to HPV-B19 infection. Conservative management with diuretics gradually improved HF symptoms over a period of 2 weeks. HPV-B19 infection in adult patients with HS rarely results in severe HLH, but conservative therapy may improve the symptoms. Nonetheless, a careful follow-up is required after HLH improves because viral myocarditis can develop, as was seen in our patient.